I'm a co-founder of NorthBridge Energy Partners, LLC., a consulting firm that helps companies connect assets to power grids. I'm also a former Senior VP of Energy Technology Services for Constellation NewEnergy, Inc., and have 20+ years of experience in the energy industry. I've written for the Boston Business Journal, Mass High Tech and several other online industry publications. I have a B.A. from Williams College and a Masters from Tufts University’s Fletcher School.

Underground Coal Gasification: A Trend Worth Watching

Five years ago, natural gas prices were soaring and it seemed there would be some kind of concerted approach to managing our carbon emissions. At that time underground coal gasification (UCG, also known as in-situ coal gasification or ISCG) was increasingly seen as a relatively low-impact way of tapping the huge US coal resource, while potentially managing emissions. But UCG never really got invited to the ball, as cheap shale gas crashed the party and stuck around.

Coal Gasification is a well-known, tried and true technology, dating back to the mid-1800s. Town gas, as it was then known, lit the streets of London and other cities in the 1860s, (thereby helping to save the sperm whale – whose oil was used in lighting municipalities around the globe – from extinction).

UCG essentially involves a process that captures the imagination: heating underground coal seams to the point of combustion. It involves drilling two wells – at some distance from each other – into the coal seam. The first well supplies oxidants (a mixture of water and air or water and oxygen), which are injected into the location where the process is actually occurring. The second well permits the syngas produced to escape under pressure to the surface. This gas contains approximately 80% of the original energy content of the coal, and is a combination of hydrogen, carbon monoxide, carbon dioxide, and methane.

The concept of heating underground coal to a combustion point may lead one to recall Centralia, PA, an abandoned town in Pennsylvania sitting on a coal seam which has been burning for 50 years, but the UCG controlled process makes that outcome highly unlikely.

The allure of the technology is that it has four distinct potential advantages over today’s traditional approaches to coal mining:

1) it vastly increases the amount of energy available because it allows one to access otherwise uneconomic coal seams through targeted drilling.

2) it has a lower environmental footprint, as it does not involve strip mining or mountaintop removal.

4) it may create a low-carbon way of exploiting the coal resource. It facilitates a cheaper way of capturing greenhouse gases, which can either be pumped back into the coal seam, or be re-used to inject oilfields to increase recovery rates (OK, even I see the irony here).

Ironically as well, the shale gas revolution led by Chesapeake and others is helping to improve a technology which had traditionally been somewhat limited and slow to improve. While shale gas has hurt the economics for UCG in the US, it has also led to improvements in seismic technology and horizontal drilling that may vastly improve the economics in the long term. Richard Morse, director of coal and carbon research at Stanford University in Palo Alto, California recently stated “The shale gas revolution is opening doors for the coal gas revolution… We knew it was there but couldn’t get it out in a cost- effective way.” Now that may all be changing.

While US shale gas at $3.75 is currently far cheaper than the $6 per mmBtu cost of fuel for a typical UCG project (per estimates from Julio Freedman chief energy technologist at Lawrence Livermore National Laboratory), the UCG costs are falling. Houston-based Laurus Energy, which specializes in UGC, is betting that efficiencies will increase and costs will continue come down. They are working on a project in the Cook Inlet of Alaska that would provide enough syngas to fuel a 100 MW power plant, as well as investigating opportunities for UGC in Alberta and Wyoming. And last year Peabody Coal paid $6.5 mn for 29 leases of Wyoming coal reserves that are far too deep for traditional mining, but which would be exploited by UCG.

In other parts of the world, where coal seams are deeper and gas prices are well over $10 per mmBtu, UGC is making more progress. China, India, South Africa, New Zealand, Australia, and other countries are pushing the technology harder. Currently, China is reported to have approximately 30 plants in various stages of development. India is reviewing the the process intently, as it has a serious problem accessing its coal supply. South Africa has a long history of syngas production (since the apartheid days), and has pilot facilities that have been operating for some years. Australia possesses a site which has been operating for over a decade, and they use the process to produce cost-competitive diesel fuel.

Even hydrocarbon-rich Canada is in the game, with its soon-to-be-completed $1.5 bn Swan Hills Synfuels project in Alberta. This facility will exploit an otherwise inaccessible coal seam almost a mile deep, and utilize the gas in a 300 MW power plant, at costs that are said to be “very competitive.” Following on the heels of a successful demonstration project in 2009, the new facility is expected to start delivering gas in 2015. http://swanhills-synfuels.com The project will also capture over 1.3 million tonnes of CO2 each year, to be utilized for enhanced oil recovery.

With shale gas still very cheap in North America, Underground Coal Gasification may not make major progress on this continent anytime soon. But here’s the thing: ten years ago, we didn’t put much stock in the future of shale gas. Meanwhile, the global coal resource is enormous. Natural gas is a lot more expensive in other parts of the world. And lots of other countries are diligently running their experiments. Don’t be surprised if we hear a lot more about UGC in the years to come.

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It is not possile to look down through 200 to 2000 feet of rock and soil to see exactly what is there.

It is not possile to control or extunguish coal seam fires, in many cases, the exact source can’t located or accessed. Imagine trying to put out a forest fire from 1/2 a mile away, with a blindfold on.

Coal is used to smelt iron ore into steel. A coal fire is certainly hot enough to vaporize any of the elements listed(and many others)—ESPECIALLY mercury(Hg) which has a relatively low sublimation temperature.

Coal seams are relatively soft formations formed between layers of harder less permeable rock. Coal seams for the most part are natural underground aquifers. Setting fire to the coal can release toxins safely sequestered in the carbon crystal structure of the coal for millions of years—create ash, and release, sulphur, chlorine and bromines—-acid formers, your groundwater becomes an acid bath. This is the cause of the many many enormous fish kills downstream from mine run offs.

In Situ Coal Gasification is a particulary BAD idea.

ISCG rivals nuclear weapons in the potential damages that could occur.

We have msny, much better and safer means of providing energy we need at our disposal.

Thank you for the comments. With seismic, you can actually see a good deal. 3D seismic is even better. The technology has been in use and while you heat to pointing of combustion, you control the input of oxygen so apparently you can kill the process. The process is far below the water table – as deep as a mile – so it may have different issues that typical mining pollution, and apparently one can clean the gases which are piped out. Some environmentalists are in favor if it takes out regular coal mining. Perhaps a greater problem is that the process unlocks yet one more source of carbon: it would seem we have enough of those already. I am not a proponent of the technology nor a detractor. I just want to make people aware of it as a potential future trend to watch. And I completely agree with our sentiment that we should look at all of these technologies with a skeptic’s eye. Too much at stake not to…

Centralia – as far as I understand it, was a fire that got out of control and nobody could control the sources of oxygen. Apparently, it’s a much shallower fire that has access to natural oxygen, whilst the UCG process strictly controls the amount of O2 available to the process. Sorry for missing this commment last month.

Thanks for posting the news on Coal Gasification. Going further, I’d like to mention that the underground gasification technology to produce urea fertilizers for farmlands will be a great achievement in the agriculture industry. However, I’m a bit concerned about those days when the natural resource of coal will be at competitive stage. Can’t we come up with some alternative Eco-friendly process which may allow minimum usage of coal?